Dump the weight machines for free weights if possible. Then do the main compound lifts like Deadlifts, Squats, Bent over rows, Military presses, Benches.
What's your targets? Gain muscle? Lose fat?
When weight lifting at the gym, the amount of weight you lift, is just as important as how you recover. At the gym, your not building your muscles up, your breaking them down, then after the gym, they recover, if you give them the right foods they can recover bigger and better.
If your doing light cardio, then to be honest, only one rest day a week is sufficient, because your not really pushing your body.
But, if your doing either heavy heavy cardio, or weight lifting, you need more time. I only go to the gym to weightlift three times a week, and then do 2 light cardio sessions a week, whether that be walking for an hour, or half an hour cycle.
Recovery is vital, but more importantly, what are your goals? If your just going to the gym with no ideas of what you want to do, then you'll really get nowhere.